Shelf structure



FIG. 1 is a perspective view of a shelf structure in accordance with the present invention.

FIG. 2 is a right side elevational view thereof.

FIG. 3 is a left side elevational view thereof.

FIG. 4 is a front view thereof.

FIG. 5 is a rear view thereof.

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The design for a shelf structure, as shown and described. 